Smith wrote for the news outlet Politico from 2008 to 2011, joining as that site expanded and became frequently cited during the 2008 presidential election. He became one of its most prominent writers, bloggers, and political journalists.

In December 2011, he was named editor-in-chief of Buzzfeed News.[1] Smith explained that he would be leaving his Politico blog but he would still write for the publication weekly.[5]

Joining Politico from the New York Daily News in 2007, Smith covered the Democratic presidential primary for Politico in 2008. He covered controversies including Barack Obama's contacts with former Weatherman Bill Ayers[6] and conspiracy theories about Obama's citizenship[7] and Barack Obama religion conspiracy theories.[8] Smith reported erroneously during that 2008 campaign that John Edwards would be dropping out of the race[9] before the press conference at which Edwards announced that his wife Elizabeth had cancer. Smith later posted an apology[10] and retracted the story. In 2010, he reported on a confidential Republican National Committee fundraising presentation counseling the party to capitalize on fear.[11]

In January 2017, Smith, as Buzzfeed's editor, published a highly controversial 35-page dossier about Donald Trump, which major news organizations, including the New York Times and NBC News, refused to publish due to lack of credible evidence. Smith defended his decision by saying, "We have always erred on the side of publishing."[12]

Since working at BuzzFeed, Smith has focused on strengthening the organization's investigative journalism unit.[13][14] In 2012, Fast Company placed Smith on its "100 Most Creative" list.[15] He and Buzzfeed co-founder Jonah Peretti were listed as two of the most powerful people in the media by The Hollywood Reporter.[13]

Smith interviewed Obama in early 2015 for Buzzfeed's first presidential interview.[16]